Message-Id: <20220301194951.106227-1-hsiangkao@linux.alibaba.com>
Date:   Wed,  2 Mar 2022 03:49:50 +0800
From:   Gao Xiang <hsiangkao@...ux.alibaba.com>
To:     linux-erofs@...ts.ozlabs.org, Chao Yu <chao@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Gao Xiang <hsiangkao@...ux.alibaba.com>
Subject: [PATCH 1/2] erofs: get rid of `struct z_erofs_collector'

Avoid `struct z_erofs_collector' since there is another context
structure called "struct z_erofs_decompress_frontend".

No logic changes.

Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
---
 fs/erofs/zdata.c | 163 ++++++++++++++++++++++-------------------------
 1 file changed, 77 insertions(+), 86 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 423bc1a61da5..2673fc105861 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -192,7 +192,10 @@ enum z_erofs_collectmode {
 	COLLECT_PRIMARY_FOLLOWED,
 };
 
-struct z_erofs_collector {
+struct z_erofs_decompress_frontend {
+	struct inode *const inode;
+	struct erofs_map_blocks map;
+
 	struct z_erofs_pagevec_ctor vector;
 
 	struct z_erofs_pcluster *pcl, *tailpcl;
@@ -202,13 +205,6 @@ struct z_erofs_collector {
 	z_erofs_next_pcluster_t owned_head;
 
 	enum z_erofs_collectmode mode;
-};
-
-struct z_erofs_decompress_frontend {
-	struct inode *const inode;
-
-	struct z_erofs_collector clt;
-	struct erofs_map_blocks map;
 
 	bool readahead;
 	/* used for applying cache strategy on the fly */
@@ -216,30 +212,26 @@ struct z_erofs_decompress_frontend {
 	erofs_off_t headoffset;
 };
 
-#define COLLECTOR_INIT() { \
-	.owned_head = Z_EROFS_PCLUSTER_TAIL, \
-	.mode = COLLECT_PRIMARY_FOLLOWED }
-
 #define DECOMPRESS_FRONTEND_INIT(__i) { \
-	.inode = __i, .clt = COLLECTOR_INIT(), \
-	.backmost = true, }
+	.inode = __i, .owned_head = Z_EROFS_PCLUSTER_TAIL, \
+	.mode = COLLECT_PRIMARY_FOLLOWED }
 
 static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES];
 static DEFINE_MUTEX(z_pagemap_global_lock);
 
-static void preload_compressed_pages(struct z_erofs_collector *clt,
+static void preload_compressed_pages(struct z_erofs_decompress_frontend *fe,
 				     struct address_space *mc,
 				     enum z_erofs_cache_alloctype type,
 				     struct page **pagepool)
 {
-	struct z_erofs_pcluster *pcl = clt->pcl;
+	struct z_erofs_pcluster *pcl = fe->pcl;
 	bool standalone = true;
 	gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) |
 			__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
 	struct page **pages;
 	pgoff_t index;
 
-	if (clt->mode < COLLECT_PRIMARY_FOLLOWED)
+	if (fe->mode < COLLECT_PRIMARY_FOLLOWED)
 		return;
 
 	pages = pcl->compressed_pages;
@@ -288,7 +280,7 @@ static void preload_compressed_pages(struct z_erofs_collector *clt,
 	 * managed cache since it can be moved to the bypass queue instead.
 	 */
 	if (standalone)
-		clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
+		fe->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
 }
 
 /* called by erofs_shrinker to get rid of all compressed_pages */
@@ -350,47 +342,47 @@ int erofs_try_to_free_cached_page(struct page *page)
 }
 
 /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */
-static bool z_erofs_try_inplace_io(struct z_erofs_collector *clt,
+static bool z_erofs_try_inplace_io(struct z_erofs_decompress_frontend *fe,
 				   struct page *page)
 {
-	struct z_erofs_pcluster *const pcl = clt->pcl;
+	struct z_erofs_pcluster *const pcl = fe->pcl;
 
-	while (clt->icpage_ptr > pcl->compressed_pages)
-		if (!cmpxchg(--clt->icpage_ptr, NULL, page))
+	while (fe->icpage_ptr > pcl->compressed_pages)
+		if (!cmpxchg(--fe->icpage_ptr, NULL, page))
 			return true;
 	return false;
 }
 
 /* callers must be with collection lock held */
-static int z_erofs_attach_page(struct z_erofs_collector *clt,
+static int z_erofs_attach_page(struct z_erofs_decompress_frontend *fe,
 			       struct page *page, enum z_erofs_page_type type,
 			       bool pvec_safereuse)
 {
 	int ret;
 
 	/* give priority for inplaceio */
-	if (clt->mode >= COLLECT_PRIMARY &&
+	if (fe->mode >= COLLECT_PRIMARY &&
 	    type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
-	    z_erofs_try_inplace_io(clt, page))
+	    z_erofs_try_inplace_io(fe, page))
 		return 0;
 
-	ret = z_erofs_pagevec_enqueue(&clt->vector, page, type,
+	ret = z_erofs_pagevec_enqueue(&fe->vector, page, type,
 				      pvec_safereuse);
-	clt->cl->vcnt += (unsigned int)ret;
+	fe->cl->vcnt += (unsigned int)ret;
 	return ret ? 0 : -EAGAIN;
 }
 
-static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt)
+static void z_erofs_try_to_claim_pcluster(struct z_erofs_decompress_frontend *f)
 {
-	struct z_erofs_pcluster *pcl = clt->pcl;
-	z_erofs_next_pcluster_t *owned_head = &clt->owned_head;
+	struct z_erofs_pcluster *pcl = f->pcl;
+	z_erofs_next_pcluster_t *owned_head = &f->owned_head;
 
 	/* type 1, nil pcluster (this pcluster doesn't belong to any chain.) */
 	if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL,
 		    *owned_head) == Z_EROFS_PCLUSTER_NIL) {
 		*owned_head = &pcl->next;
 		/* so we can attach this pcluster to our submission chain. */
-		clt->mode = COLLECT_PRIMARY_FOLLOWED;
+		f->mode = COLLECT_PRIMARY_FOLLOWED;
 		return;
 	}
 
@@ -401,24 +393,24 @@ static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt)
 	if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
 		    *owned_head) == Z_EROFS_PCLUSTER_TAIL) {
 		*owned_head = Z_EROFS_PCLUSTER_TAIL;
-		clt->mode = COLLECT_PRIMARY_HOOKED;
-		clt->tailpcl = NULL;
+		f->mode = COLLECT_PRIMARY_HOOKED;
+		f->tailpcl = NULL;
 		return;
 	}
 	/* type 3, it belongs to a chain, but it isn't the end of the chain */
-	clt->mode = COLLECT_PRIMARY;
+	f->mode = COLLECT_PRIMARY;
 }
 
-static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
+static int z_erofs_lookup_collection(struct z_erofs_decompress_frontend *fe,
 				     struct inode *inode,
 				     struct erofs_map_blocks *map)
 {
-	struct z_erofs_pcluster *pcl = clt->pcl;
+	struct z_erofs_pcluster *pcl = fe->pcl;
 	struct z_erofs_collection *cl;
 	unsigned int length;
 
 	/* to avoid unexpected loop formed by corrupted images */
-	if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) {
+	if (fe->owned_head == &pcl->next || pcl == fe->tailpcl) {
 		DBG_BUGON(1);
 		return -EFSCORRUPTED;
 	}
@@ -449,15 +441,15 @@ static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
 	}
 	mutex_lock(&cl->lock);
 	/* used to check tail merging loop due to corrupted images */
-	if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
-		clt->tailpcl = pcl;
+	if (fe->owned_head == Z_EROFS_PCLUSTER_TAIL)
+		fe->tailpcl = pcl;
 
-	z_erofs_try_to_claim_pcluster(clt);
-	clt->cl = cl;
+	z_erofs_try_to_claim_pcluster(fe);
+	fe->cl = cl;
 	return 0;
 }
 
-static int z_erofs_register_collection(struct z_erofs_collector *clt,
+static int z_erofs_register_collection(struct z_erofs_decompress_frontend *fe,
 				       struct inode *inode,
 				       struct erofs_map_blocks *map)
 {
@@ -485,8 +477,8 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
 			Z_EROFS_PCLUSTER_FULL_LENGTH : 0);
 
 	/* new pclusters should be claimed as type 1, primary and followed */
-	pcl->next = clt->owned_head;
-	clt->mode = COLLECT_PRIMARY_FOLLOWED;
+	pcl->next = fe->owned_head;
+	fe->mode = COLLECT_PRIMARY_FOLLOWED;
 
 	cl = z_erofs_primarycollection(pcl);
 	cl->pageofs = map->m_la & ~PAGE_MASK;
@@ -512,18 +504,18 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
 		}
 
 		if (grp != &pcl->obj) {
-			clt->pcl = container_of(grp,
+			fe->pcl = container_of(grp,
 					struct z_erofs_pcluster, obj);
 			err = -EEXIST;
 			goto err_out;
 		}
 	}
 	/* used to check tail merging loop due to corrupted images */
-	if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
-		clt->tailpcl = pcl;
-	clt->owned_head = &pcl->next;
-	clt->pcl = pcl;
-	clt->cl = cl;
+	if (fe->owned_head == Z_EROFS_PCLUSTER_TAIL)
+		fe->tailpcl = pcl;
+	fe->owned_head = &pcl->next;
+	fe->pcl = pcl;
+	fe->cl = cl;
 	return 0;
 
 err_out:
@@ -532,18 +524,18 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
 	return err;
 }
 
-static int z_erofs_collector_begin(struct z_erofs_collector *clt,
+static int z_erofs_collector_begin(struct z_erofs_decompress_frontend *fe,
 				   struct inode *inode,
 				   struct erofs_map_blocks *map)
 {
 	struct erofs_workgroup *grp;
 	int ret;
 
-	DBG_BUGON(clt->cl);
+	DBG_BUGON(fe->cl);
 
 	/* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous collection */
-	DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_NIL);
-	DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
+	DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_NIL);
+	DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
 
 	if (map->m_flags & EROFS_MAP_META) {
 		if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
@@ -555,28 +547,28 @@ static int z_erofs_collector_begin(struct z_erofs_collector *clt,
 
 	grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT);
 	if (grp) {
-		clt->pcl = container_of(grp, struct z_erofs_pcluster, obj);
+		fe->pcl = container_of(grp, struct z_erofs_pcluster, obj);
 	} else {
 tailpacking:
-		ret = z_erofs_register_collection(clt, inode, map);
+		ret = z_erofs_register_collection(fe, inode, map);
 		if (!ret)
 			goto out;
 		if (ret != -EEXIST)
 			return ret;
 	}
 
-	ret = z_erofs_lookup_collection(clt, inode, map);
+	ret = z_erofs_lookup_collection(fe, inode, map);
 	if (ret) {
-		erofs_workgroup_put(&clt->pcl->obj);
+		erofs_workgroup_put(&fe->pcl->obj);
 		return ret;
 	}
 
 out:
-	z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS,
-				  clt->cl->pagevec, clt->cl->vcnt);
+	z_erofs_pagevec_ctor_init(&fe->vector, Z_EROFS_NR_INLINE_PAGEVECS,
+				  fe->cl->pagevec, fe->cl->vcnt);
 	/* since file-backed online pages are traversed in reverse order */
-	clt->icpage_ptr = clt->pcl->compressed_pages +
-			z_erofs_pclusterpages(clt->pcl);
+	fe->icpage_ptr = fe->pcl->compressed_pages +
+			z_erofs_pclusterpages(fe->pcl);
 	return 0;
 }
 
@@ -610,24 +602,24 @@ static void z_erofs_collection_put(struct z_erofs_collection *cl)
 	erofs_workgroup_put(&pcl->obj);
 }
 
-static bool z_erofs_collector_end(struct z_erofs_collector *clt)
+static bool z_erofs_collector_end(struct z_erofs_decompress_frontend *fe)
 {
-	struct z_erofs_collection *cl = clt->cl;
+	struct z_erofs_collection *cl = fe->cl;
 
 	if (!cl)
 		return false;
 
-	z_erofs_pagevec_ctor_exit(&clt->vector, false);
+	z_erofs_pagevec_ctor_exit(&fe->vector, false);
 	mutex_unlock(&cl->lock);
 
 	/*
 	 * if all pending pages are added, don't hold its reference
 	 * any longer if the pcluster isn't hosted by ourselves.
 	 */
-	if (clt->mode < COLLECT_PRIMARY_FOLLOWED_NOINPLACE)
+	if (fe->mode < COLLECT_PRIMARY_FOLLOWED_NOINPLACE)
 		z_erofs_collection_put(cl);
 
-	clt->cl = NULL;
+	fe->cl = NULL;
 	return true;
 }
 
@@ -651,7 +643,6 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	struct inode *const inode = fe->inode;
 	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
 	struct erofs_map_blocks *const map = &fe->map;
-	struct z_erofs_collector *const clt = &fe->clt;
 	const loff_t offset = page_offset(page);
 	bool tight = true;
 
@@ -672,7 +663,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	if (offset + cur >= map->m_la &&
 	    offset + cur < map->m_la + map->m_llen) {
 		/* didn't get a valid collection previously (very rare) */
-		if (!clt->cl)
+		if (!fe->cl)
 			goto restart_now;
 		goto hitted;
 	}
@@ -680,7 +671,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	/* go ahead the next map_blocks */
 	erofs_dbg("%s: [out-of-range] pos %llu", __func__, offset + cur);
 
-	if (z_erofs_collector_end(clt))
+	if (z_erofs_collector_end(fe))
 		fe->backmost = false;
 
 	map->m_la = offset + cur;
@@ -693,11 +684,11 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	if (!(map->m_flags & EROFS_MAP_MAPPED))
 		goto hitted;
 
-	err = z_erofs_collector_begin(clt, inode, map);
+	err = z_erofs_collector_begin(fe, inode, map);
 	if (err)
 		goto err_out;
 
-	if (z_erofs_is_inline_pcluster(clt->pcl)) {
+	if (z_erofs_is_inline_pcluster(fe->pcl)) {
 		void *mp;
 
 		mp = erofs_read_metabuf(&fe->map.buf, inode->i_sb,
@@ -709,8 +700,8 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 			goto err_out;
 		}
 		get_page(fe->map.buf.page);
-		WRITE_ONCE(clt->pcl->compressed_pages[0], fe->map.buf.page);
-		clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
+		WRITE_ONCE(fe->pcl->compressed_pages[0], fe->map.buf.page);
+		fe->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
 	} else {
 		/* preload all compressed pages (can change mode if needed) */
 		if (should_alloc_managed_pages(fe, sbi->opt.cache_strategy,
@@ -719,7 +710,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 		else
 			cache_strategy = DONTALLOC;
 
-		preload_compressed_pages(clt, MNGD_MAPPING(sbi),
+		preload_compressed_pages(fe, MNGD_MAPPING(sbi),
 					 cache_strategy, pagepool);
 	}
 
@@ -730,8 +721,8 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	 * those chains are handled asynchronously thus the page cannot be used
 	 * for inplace I/O or pagevec (should be processed in strict order.)
 	 */
-	tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED &&
-		  clt->mode != COLLECT_PRIMARY_FOLLOWED_NOINPLACE);
+	tight &= (fe->mode >= COLLECT_PRIMARY_HOOKED &&
+		  fe->mode != COLLECT_PRIMARY_FOLLOWED_NOINPLACE);
 
 	cur = end - min_t(unsigned int, offset + end - map->m_la, end);
 	if (!(map->m_flags & EROFS_MAP_MAPPED)) {
@@ -746,18 +737,18 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 				Z_EROFS_VLE_PAGE_TYPE_TAIL_SHARED));
 
 	if (cur)
-		tight &= (clt->mode >= COLLECT_PRIMARY_FOLLOWED);
+		tight &= (fe->mode >= COLLECT_PRIMARY_FOLLOWED);
 
 retry:
-	err = z_erofs_attach_page(clt, page, page_type,
-				  clt->mode >= COLLECT_PRIMARY_FOLLOWED);
+	err = z_erofs_attach_page(fe, page, page_type,
+				  fe->mode >= COLLECT_PRIMARY_FOLLOWED);
 	/* should allocate an additional short-lived page for pagevec */
 	if (err == -EAGAIN) {
 		struct page *const newpage =
 				alloc_page(GFP_NOFS | __GFP_NOFAIL);
 
 		set_page_private(newpage, Z_EROFS_SHORTLIVED_PAGE);
-		err = z_erofs_attach_page(clt, newpage,
+		err = z_erofs_attach_page(fe, newpage,
 					  Z_EROFS_PAGE_TYPE_EXCLUSIVE, true);
 		if (!err)
 			goto retry;
@@ -773,7 +764,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	/* bump up the number of spiltted parts of a page */
 	++spiltted;
 	/* also update nr_pages */
-	clt->cl->nr_pages = max_t(pgoff_t, clt->cl->nr_pages, index + 1);
+	fe->cl->nr_pages = max_t(pgoff_t, fe->cl->nr_pages, index + 1);
 next_part:
 	/* can be used for verification */
 	map->m_llen = offset + cur - map->m_la;
@@ -1309,7 +1300,7 @@ static void z_erofs_submit_queue(struct super_block *sb,
 	z_erofs_next_pcluster_t qtail[NR_JOBQUEUES];
 	struct z_erofs_decompressqueue *q[NR_JOBQUEUES];
 	void *bi_private;
-	z_erofs_next_pcluster_t owned_head = f->clt.owned_head;
+	z_erofs_next_pcluster_t owned_head = f->owned_head;
 	/* bio is NULL initially, so no need to initialize last_{index,bdev} */
 	pgoff_t last_index;
 	struct block_device *last_bdev;
@@ -1417,7 +1408,7 @@ static void z_erofs_runqueue(struct super_block *sb,
 {
 	struct z_erofs_decompressqueue io[NR_JOBQUEUES];
 
-	if (f->clt.owned_head == Z_EROFS_PCLUSTER_TAIL)
+	if (f->owned_head == Z_EROFS_PCLUSTER_TAIL)
 		return;
 	z_erofs_submit_queue(sb, f, pagepool, io, &force_fg);
 
@@ -1517,7 +1508,7 @@ static int z_erofs_readpage(struct file *file, struct page *page)
 	err = z_erofs_do_read_page(&f, page, &pagepool);
 	z_erofs_pcluster_readmore(&f, NULL, 0, &pagepool, false);
 
-	(void)z_erofs_collector_end(&f.clt);
+	(void)z_erofs_collector_end(&f);
 
 	/* if some compressed cluster ready, need submit them anyway */
 	z_erofs_runqueue(inode->i_sb, &f, &pagepool,
@@ -1567,7 +1558,7 @@ static void z_erofs_readahead(struct readahead_control *rac)
 		put_page(page);
 	}
 	z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false);
-	(void)z_erofs_collector_end(&f.clt);
+	(void)z_erofs_collector_end(&f);
 
 	z_erofs_runqueue(inode->i_sb, &f, &pagepool,
 			 z_erofs_get_sync_decompress_policy(sbi, nr_pages));
-- 
2.24.4

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